I know it's only a GT, but this has to be one of the cheapest but effective mods you can do.
Before

After


Yes, I know the badges need to come off, but I'll do that when I get a couple of days to machine polish it. Also, it has been mentioned, and it also says in the fitting instructions that the original pipes have to be cut. This is not the case. They fit perfectly as they are. Just push them on and tap them home with a hammer and a block of wood. Job done.